The present invention relates to a system for measuring, and assisting in the alignment and repair, of damaged or potentially damaged structural members.
The invention has been developed primarily for use in the automotive industry, and more particularly in the panel beating trade. The invention will therefore be described with reference to this application. It will be appreciated, however, that the invention is not limited to this particular field of use.
In the manufacture of motor vehicles, it is common practice to provide specific datum points in the structure to assist in xe2x80x9cjiggingxe2x80x9d the vehicle during manufacture, and in checking the dimensional accuracy of the finished product. These datum points can take various forms such as holes in the chassis, male or female threaded members such as bolt heads, nuts or studs, and other formations such as pins, lugs and suspension mounting points. They may be spaced apart in both vertical and horizontal planes. The datum points vary significantly from model to model according to various design parameters and practical convenience.
Numerous types of known apparatus are designed to permit measurements to be taken between various datum points on a given vehicle. By comparison with reference charts provided by the manufacturer, or with corresponding measurements taken on the opposite side of the vehicle, such equipment provides an absolute or at least a relative indication of the extent of structural misalignment. This facilitates the evaluation and repair of damaged or potentially damaged vehicles by panel beaters. Most known devices, however, have been found to be inadequate in various respects.
One type of prior art device consists in a peripheral reference frame rotatably or otherwise connected to a floor mounted anchorage assembly, so as to extend generally around the vehicle. Such devices are not adapted for direct connection to the datum points on the vehicle, and so are not able to provide an accurate or direct quantitative correlation between the various datum points and the manufacturers specifications. At best, they provide a relative measure of the inconsistency between comparable points on opposite sides of the vehicle. This is of little assistance if both sides of the vehicle have been damaged, and in any case will not reveal distortion in certain planes. Moreover, such devices tend to be structurally flimsy, and are inherently prone to excessive deflection, particularly adjacent the front and rear extremities of the vehicle where accurate measurement is critical. Further, in such measurement systems, it is difficult or impossible to align the vehicle precisely with the floor mounted anchorage assembly. For these reasons, such devices are often not capable even of providing consistent comparative measurements between corresponding points on the vehicle, which is necessary to provide a reliable measure of the degree of misalignment to the required level of accuracy.
Other known devices are adapted for direct connection to specific datum points, and so are capable of correlating measurements between these points on the vehicle with dimensional specifications provided by the manufacturer. However, most such devices are complex, expensive, cumbersome, involve a relatively large number of components, and are generally difficult and time consuming to use. Furthermore, most known devices of this type are capable only of providing quantitative measurements between longitudinally or transversely spaced datum points. As such, they cannot usually detect parallelogram type deflection in the vehicle frame, or deformation in the body panels beyond certain datum points.
Some devices are known which are adapted for direct connection to the datum points on the vehicle and are also capable of providing diagonal and other non-orthogonal measurements. There is a significant remaining difficulty, however, in that many of the measurements provided on vehicle manufacturers"" specification sheets are defined relative to arbitrary reference planes, which are usually different from the inherent reference planes associated with the measurement apparatus. Consequently, as each measurement is taken, it is necessary for the operator to perform an arithmetic calculation in order to correlate the actual measurements taken with the reference data and thereby ascertain the absolute magnitude of the extent of misalignment. These calculations can become complex, particularly where a number of correction factors or cumulative measurements are involved, and this gives rise to a significant possibility for human error.
Partly because of this difficulty dedicated jigs, frames or the like are sometimes manufactured for certain common makes and models of vehicle. However, these tend to be expensive and require considerable set up time. Consequently, such devices tend only to be economically viable in connection with major repairs and are not readily applicable to a wide range of vehicles.
A further difficulty with known systems is that there is no means for verifying after the event the extent of initial misalignment or the deviation from the manufacturer""s specifications after repair. As a result, vehicle repairs can be substandard and once the vehicle has been reassembled, the accuracy of the repairs can be difficult to check. Insurance companies are increasingly requiring quality assurance procedures to provide a means of confirming the damage to, and the subsequent rectification of, the vehicle in quantitative terms. Currently known systems do not enable this to be done in a convenient, accurate, reliable and cost effective manner.
It is an object of the present invention to overcome or substantially ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.
Accordingly, the invention provides a vehicle alignment gauging system including measuring means, output signal generation means adapted to generate an output signal corresponding to dimensions indicated by the measuring means, storage means to store reference data corresponding to standard reference dimensions for a selected vehicle, comparator means to compare the output signal with a selected reference dimension from the storage means and to generate an error signal indicative of the variation therebetween, and variation display means to provide a visual indication of the magnitude of the variation, thereby in use to provide a quantitative indication of structural misalignment.
Preferably, the measuring means include an extendable measuring tape, and the output signal is indicative of an operative or extended length of the tape.
Preferably, the output signal generation means include a position transducer adapted to generate the output signal in the form of an electric current or voltage, indicative of the extended length of the measuring tape.
Preferably, the system further includes output signal display means to display a visual indication of the extended length of the measuring tape according to the output signal, thereby to permit visual correlation between indicia on the measuring tape and the output signal.
Preferably, the system includes a pair of said measuring tapes, one being adapted for measurement in horizontal planes and the other being adapted for measurement in vertical planes. Preferably, the measuring tapes are supported in mutually orthogonal relationship in or on a common housing.
Preferably, the output signal display means associated with each of the measuring tapes is disposed on or adjacent the housing. The housing preferably also includes a xe2x80x9cblack boxxe2x80x9d containing electronic control and signal processing circuitry.
Preferably, the storage means is associated with a portable computer and may include a compact disc, a floppy disk, an internal disk drive, an external disk drive, a magnetic tape drive, random access memory (RAM), read only memory (ROM), or any other suitable electronic or magnetic storage mechanism.
Preferably, the comparator means takes the form of software associated with the computer. The software is preferably configured to perform a sequence of operations using the reference data and the output signal in order to generate the error signal. Preferably, the software is also configured to enable an operator to select reference dimensions from a range of standard reference dimensions, contained in the storage means.
Preferably, the variation display means are disposed on or adjacent the housing to provide direct feedback of the error signal to the operator while working on the vehicle.
Preferably, recordal means are adapted to record the error signal in relation to the corresponding reference dimension in response to a command input by the operator, thereby to provide a permanent record of the extent of structural deviation from the manufacturer""s specification, both before and after repair work has been carried out
Preferably, the system further includes a remotely operable scrolling mechanism located on or adjacent the housing, to permit the operator to scroll through a range of preselected reference dimensions and to view on the variation display means a corresponding sequence of deviations while working on the vehicle.
Preferably, the system further includes a datum bar, a pair of first carriage assemblies slidably mounted to the datum bar, attachment means adapted releasably to secure each of said first carriage assemblies to a respective datum point on the vehicle and thereby to suspend the datum bar in a transverse orientation beneath the vehicle, and a trammel bar connected at one end to said datum bar by connection means, the connection means being adjustable to selected positions along the datum bar and permitting a degree of universal movement of the trammel bar relative to the datum bar.
Preferably, the housing is adapted for mounting on the trammel bar to provide measurements relative to the datum bar and hence relative to datum points on the vehicle.
Preferably, the housing further includes a slidable reference pointer adapted for connection to the vertically oriented measuring tape and adapted for engagement with selected datum points on the vehicle with the trammel bar in a horizontal orientation. In this way, the vertical tape provides a measure indicative of the vertical distance between the datum bar and the reference pointer, and the horizontal tape provides a measure of the horizontal distance between the datum bar and the reference pointer.